Method of controlling an upshift of a transmission

Abstract

A method of controlling a transmission includes determining if an internal combustion engine of the vehicle is currently operating with active fuel management, or if the internal combustion engine is currently operating without active fuel management. The vehicle controller further determines if a possible engine torque is equal to, greater than, or less than a required engine torque. The transmission is upshifted when the internal combustion engine is currently operating with active fuel management, and when the possible engine torque is equal to or greater than the required engine torque. When the possible engine torque is less than the required engine torque, active fuel management is exited so that the internal combustion engine is currently operating without active fuel management. When the internal combustion engine is currently operating without active fuel management, the vehicle controller upshifts the transmission from the current gear ratio to the higher gear ratio.

The invention claimed is: 
     
       1. A method of controlling a transmission of a vehicle, the method compromising:
 determining if an internal combustion engine of the vehicle is currently operating with active fuel management, in which a portion of a total number of cylinders of the internal combustion engine are deactivated, or if the internal combustion engine is currently operating without active fuel management, in which all of the cylinders of the internal combustion engine are active, with a vehicle controller; 
 determining if a possible engine torque, which is an amount of engine torque that may be produced by the internal combustion engine while the internal combustion engine is currently operating with active fuel management, is equal to or greater than a required engine torque, which is an amount of engine torque required from the internal combustion engine to maintain an axle torque when the transmission is upshifted from a current gear ratio to a higher gear ratio, or if the possible engine torque is less than the required engine torque, with the vehicle controller; 
 upshifting the transmission, in which a gear ratio of the transmission is changed from the current gear ratio to the higher gear ratio, when the internal combustion engine is currently operating with active fuel management, and when the possible engine torque is equal to or greater than the required engine torque; 
 changing the current operation of the internal combustion engine from operating with active fuel management to operating without active fuel management, when the possible engine torque is less than the required engine torque, so that the internal combustion engine is currently operating without active fuel management; and 
 upshifting the transmission from the current gear ratio to the higher gear ratio, when the internal combustion engine is currently operating without active fuel management. 
 
     
     
       2. The method set forth in  claim 1  further comprising determining a current active fuel management state with the vehicle controller, wherein the current active fuel management state is one of an AFM not implemented state, AFM fully implemented state, AFM activating state, and AFM deactivating state, wherein the internal combustion engine is operating with active fuel management when the current active fuel management state is one of the AFM fully implemented state, the AFM activating state, or the AFM deactivating state, and wherein the internal combustion engine is operating without active fuel management when the current active fuel management state is the AFM not implemented state. 
     
     
       3. The method set forth in  claim 1  further comprising requesting an upshift in the gear ratio of the transmission from the current gear ratio to the higher gear ratio. 
     
     
       4. The method set forth in  claim 3  further comprising delaying the requested upshift in the gear ratio of the transmission when the internal combustion engine is currently operating with active fuel management and when the possible engine torque is less than the required engine torque, until after the current operation of the internal combustion engine is changed from operating with active fuel management to operating without active fuel management. 
     
     
       5. The method set forth in  claim 1  further comprising calculating the current axle torque with the vehicle controller. 
     
     
       6. The method set forth in  claim 5  further comprising calculating the possible engine torque with the vehicle controller. 
     
     
       7. The method set forth in  claim 6  wherein the vehicle controller calculates the possible engine torque based on a torque model that estimates the maximum torque that could be produced without exiting active fuel management. 
     
     
       8. The method set forth in  claim 5  further comprising calculating the required engine torque with the vehicle controller. 
     
     
       9. The method set forth in  claim 8  wherein the vehicle controller calculates the required engine torque based on the gear ratio of the higher gear ratio and the current axle torque. 
     
     
       10. The method set forth in  claim 1  wherein upshifting the transmission from the current gear ratio to the higher gear ratio includes actuating at least one actuator in the transmission to effect the upshift. 
     
     
       11. The method set forth in  claim 10  wherein the at least one actuator includes one of a torque transmitting mechanism, a hydraulic control valve, an electrically actuated control valve, or a linear actuator. 
     
     
       12. A method of executing a requested upshift in a transmission of a vehicle, to change a gear ratio of the transmission from a current gear ratio to a higher gear ratio, the method comprising;
 determining if a possible engine torque, which is an amount of engine torque that may be produced by an internal combustion engine while the internal combustion engine is currently operating with active fuel management, is equal to or greater than a required engine torque, which is an amount of engine torque required from the internal combustion engine to maintain an axle torque when the transmission is upshifted from the current gear ratio to the higher gear ratio, or if the possible engine torque is less than the required engine torque, with a vehicle controller; 
 changing the current operation of the internal combustion engine from operating with active fuel management to operating without active fuel management, when the possible engine torque is less than the required engine torque, so that the internal combustion engine is currently operating without active fuel management; and 
 upshifting the transmission from the current gear ratio to the higher gear ratio, when the internal combustion engine is currently operating without active fuel management. 
 
     
     
       13. The method set forth in  claim 12  further comprising upshifting the transmission when the internal combustion engine is currently operating with active fuel management, and when the possible engine torque is equal to or greater than the required engine torque. 
     
     
       14. The method set forth in  claim 12  further comprising determining if the internal combustion engine of the vehicle is currently operating with active fuel management, in which a portion of a total number of cylinders of the internal combustion engine are deactivated, or if the internal combustion engine is currently operating without active fuel management, in which all of the cylinders of the internal combustion engine are active, with the vehicle controller. 
     
     
       15. The method set forth in  claim 12  further comprising delaying the requested upshift in the gear ratio of the transmission when the internal combustion engine is currently operating with active fuel management and when the possible engine torque is less than the required engine torque, until after the current operation of the internal combustion engine is changed from operating with active fuel management to operating without active fuel management. 
     
     
       16. The method set forth in  claim 12  wherein upshifting the transmission from the current gear ratio to the higher gear ratio includes actuating at least one actuator in the transmission with the vehicle controller to effect the upshift. 
     
     
       17. The method set forth in  claim 16  wherein the at least one actuator includes one of a torque transmitting mechanism, a hydraulic control valve, an electrically actuated control valve, or a linear actuator. 
     
     
       18. The method set forth in  claim 12  further comprising calculating the current axle torque with the vehicle controller. 
     
     
       19. The method set forth in  claim 18  further comprising calculating the possible engine torque, with the vehicle controller, based on a torque model that estimates the maximum torque that could be produced without exiting active fuel management. 
     
     
       20. The method set forth in  claim 19  further comprising calculating the required engine torque, with the vehicle controller, based on the gear ratio of the higher gear ratio and the current axle torque.